DVT Flashcards
Where can DVTs occur?
- Proximal - popliteal, superficial femoral, deep femoral, common femoral, external iliac.
- Distal - soleal, peroneal veins.
What is a DVT?
Deep vein thrombosis - blood clot in a major deep vein in the leg, thigh, pelvis, or abdomen, which may result in impaired venous blood flow and consequent leg swelling and pain.
What are the risk factors for DVT?
Age, pregnancy, synthetic oestrogen, trauma, surgery especially orthopaedic and pelvic, past DVT, cancer, obesity, immobility.
What is this a presentation of?
Unilateral warm calf, tender, swelling, erythema, pitting oedema.
DVT
What is the method of risk stratification in a suspected DVT?
DVT specific Wells score:
- Active cancer (1)
- Recently bedridden >3 days or major surgery in the last 12 weeks (1)
- Paralysis, paresis or recent plaster immobilisation of affected leg (1)
- Previously documented DVT (1)
- Calf swelling >3cm more than contralateral leg (1)
What is the process of diagnosing a DVT?
- Calculate Wells score
- If unlikely, d-dimer, if this is positive then USS.
- If likely, d-dimer and USS.
What is the management for a DVT?
- FBC, PT, aPTT, LFTs, U&Es prior to anticoagulation.
- Start treatment in proximal, only start treatment in distal if symptomatic or if risk factors present.
- DOAC (dabigatran, enoxaparin) - 3 months if provoked, 6 months if unprovoked.
- TED stockings
What is the mechanism of action of heparin?
- UFH activates antithrombin which inhibits factor Xa.
2. LMWH inhibits factor Xa
What are the side effects of heparin?
- Bleeding (less so with LMWH)
- Injection site reactions
- Heparin-induced thrombocytopenia
What is the mechanism of action of warfarin?
Inhibits hepatic production of vitamin K dependent coagulation factors (2, 7, 9, 10).
What is the main side effect of warfarin?
Bleeding
What are the pharmaceutical and non-pharmaceutical interactions with warfarin?
- NSAIDs, St John’s Wort, antihistamines, some antibiotics.
2. Cranberry juice/grapefruit, moderate alcohol, sudden diet change.
What are the complications of a DVT?
- Post-thrombotic stroke - chronic obstruction of venous outflow and/or destruction of venous valves causing venous hypertension.
- Pulmonary embolism
What is the advice for DVT and travel?
- Compression stockings
- Leg exercises
- Increased water intake
- Refrain from alcohol and caffeine
- In high risk individuals - single dose LMWH may be considered.